Incidence of and risk indicators for vasa praevia: a systematic review

Abstract

Background Vasa praevia (VP) is a rare phenomenon that is assumed to increase the risk of severe complications, including fetal death. Critical data on its incidence are lacking, so there is no rational basis for prenatal screening.Objectives To review the literature on the incidence and risk indicators for VP.Search strategy We searched OVID MEDLINE, OVID EMBASE, the Cochrane Library and PubMed for case-control and cohort studies on incidence and risk indicators for VP. Selection criteria Two reviewers selected studies and scored their methodological quality.Data collection and analysis We calculated the mean incidence of VP. We constructed 2 9 2 tables cross-classifying potential risk indicators against the incidence of VP to calculate common odds ratios and 95% confidence intervals, using the Mantel-Haenszel method.Main results We included 13 studies (two prospective cohort studies, ten retrospective cohort studies and one case-control study) reporting on 569 410 patients with 325 cases of VP. Based on ten included cohort studies providing information on the incidence, the mean incidence of VP was 0.60 per 1000 pregnancies. We identified five different risk indicators and markers for VP: second-trimester placenta praevia, conception by assisted reproductive technologies, a bilobed or succenturiate placenta, umbilical cord insertion in the lower third part of the uterus at first-trimester ultrasound and velamentous cord insertion. Almost 83% of the cases of VP had one or more risk indicators.Authors' conclusions In view of the low incidence, screening for VP in an unselected population is not advised. Targeted screening of women with one or more risk indicators as a part of routine mid-gestation scanning should be considered.

Prenatal diagnosis and management of vasa previa in twin pregnancies: a case series and systematic review

“…10,[14][15][16][17][18] The incidence of VP has been reported to be as high as one in 300 pregnancies conceived after ART. 7,14 These data suggest that the incidence of VP in both singleton and multiple pregnancy gestations is likely to increase in the next decade with the increase use of ART worldwide.…”

“…[1][2][3][4][5] A recent systematic review of 10 cohort studies found that the incidence of VP is 0.6 per 1000 pregnancies. 7 Approximately 90% of women presenting with a VP also have a velamentous cord insertion (VCI) and 3-4% of women presenting with a VCI have a VP. 8 Unlike the single umbilical artery cord which is routinely recorded by midwives at birth, these cord anomalies are only recorded when associated with perinatal complications and the placental is examined by a pathologist.…”

“…Both cord anomalies are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 5 5 low-lying placenta. [1][2][3][4][5][6][7][8] VCI and VP type I are also more common in twin pregnancies and monochorionicity doubles the risk for VCI compared to dichorinicity. 11,12 Maternal smoking has been recently reported as a risk factor for VCI and thus potentially of VP.…”

“…13 Assisted reproduction technology (ART) and in vitro fertilization (IVF) in particular is associated with a higher incidence of abnormally shaped placenta, placenta previa and cord insertion outside the placental chorionic plate. 7,14 It has been hypothesized these placental and cord anomalies could be due to the inadequate orientation of the IVF blastocyst at the time of implantation or to a higher incidence of vanishing twins in IVF than in spontaneous twins. 10,[14][15][16][17][18] The incidence of VP has been reported to be as high as one in 300 pregnancies conceived after ART.…”

Re: Intimate partner violence during pregnancy and the risk for adverse infant outcomes: a systematic review and meta‐analysis

“…By contrast, the adherent or non-invasive form of PA requires either histopathological confirmation or specific clinical diagnosis using predefined criteria such as those used by the European Working Group on AIP. 2 Common placental retention may also result…”